Refrigerated Containers Research Articles

Improving Electric Power Stability and Efficiency Using an Integrated Control System for Refrigerated Containers

In this study, a method is proposed to minimize electrical load fluctuations and improve the efficiency of engine generator operation by managing refrigerated ship containers through an integrated control system. The proposed system actively controls the electrical load by assigning operational priorities based on cargo temperature deviations to existing independently operated refrigerated containers, ensuring that they operate only within the available power of the engine generator. As a result, the average specific fuel oil consumption can be reduced. A 70 h simulation of the refrigerated containers, a power system, and an integrated control system demonstrated in MATLAB/Simulink 2021b that the magnitude of electrical load fluctuations decreases from 37.6% to 9.6% of the engine generator’s rated power compared with the conventional operation of refrigerated containers. In addition, a 1.88% fuel saving is realized.

Building a physics-based virtual refrigerated container filled with fruit in ventilated packaging

We build a validated physics-based model of a refrigerated container filled with fruit in ventilated packaging. This model of a virtual container is the basis for simulations in an accompanying paper on citrus fruit shipped overseas from South Africa to Europe. The model is used to understand better how the cargo cools and when and where food quality is lost in these supply chains. We build a computational fluid dynamics model with a two-phase porous media approach that simulates the airflow in the container and the cooling process of every fruit. This container can be considered aerodynamically to be a slot-ventilated enclosure. We also model the fruit's thermally-driven quality loss. Using a two-phase porous media approach for the ventilated cargo and modeling temperature-driven fruit quality evolution are two steps forward compared to most existing physics-based refrigerated container models. We validate the porous media model implementation. We define and apply actionable metrics for every fruit inside the cargo, such as remaining shelf life upon arrival and seven-eighths cooling time.• This model can help reduce food loss and increase supply-chain resilience• This model is an essential building block of a refrigerated container's digital twin• This model can support stakeholders in improving cargo temperature control and resulting fruit quality preservation.

Airflow optimisation approaches in refrigerated containers loaded with citrus

Airflow optimisation approaches in refrigerated containers loaded with citrus

On the issue of logistic support of export of medicinal preparations of national production

The current geopolitical situation raised pointed question of developing new supply chains and looking for rolling stock to develop newly formed cargo flows, including medicinal preparations transportation. Considering necessity in timely and safe supply of medicines, it is necessary to develop set of measures permitting to implement export of this production of national industry to ensure ultimate independence from unfriendly states. The article considers main indicators of import and export operations of medicinal preparations and measures taken by the state to support industry in current conditions, requirements for international transportation of this category of goods. The measures increasing exports within the framework of the Pharmaceutical Industry Development Strategy until 2030, such as expansion of fleet of autonomous refrigerated containers, use of consolidation warehouses in Turkey and Kazakhstan to ensure decreasing of cost of multi-modal transportation of medicinal preparations, as well as validation of rolling stock in accordance with GDP requirements.

Оптимизация перевозок термочувствительных грузов в рефрижераторных контейнерах с применением альтернативных источников энергии

Purpose: to consider the main problems of transportation of temperature-sensitive cargoes in refrigerated containers (refcontainers). To show the possibilities of transportation optimization through the introduction of alternative energy sources. Methods: comparison of technical and economic indicators of diesel, hydrogen and hydrogen plants is carried out. The exergetic method of estimating the effect of replacing diesel fuel with LNG was applied. Results: the article defines the peculiarities of cargo transportation in containers with built-in refrigeration units — autonomous refcontainers. Classification of existing energy units for power supply of refcontainers is given. The design of an autonomous installation for power supply of refcontainers is described. Environmentally safe alternatives for providing autonomous power supply of refrigerating units of refrigeration containers are proposed. The advantages of autonomous power supply based on high-temperature fuel cells are presented. An autonomous power unit with liquefied natural gas (LNG) as fuel is described. The feasibility of utilization of cold from LNG regasification is analyzed in order to ensure the stability of refcontainer operation. The estimation of the expected effect from the use of alternative fuels for autonomous power supply is made. Practical significance: the obtained results can be used for modernization of low-capacity power plants used in refrigerated and other types of transport.

Long-Term Tissue Preservation at Ambient Temperature for Post-Mass Fatality Incident DNA-Based Victim Identification.

In a mass fatality incident (MFI), effective preservation of tissue samples is the cornerstone for downstream DNA-based identification of victims. This is commonly achieved through freezing of tissue samples excised from bodies/fragmented remains which may be buried or stored in refrigerated containers. This may, however, not be possible depending on the nature of the MFI; in particular, during armed conflict/war where extended periods of electrical outages would be expected. The present study compared the effectiveness of long-term tissue preservation at ambient temperatures using two commercial products (non-iodized kitchen salt and a 40% alcoholic beverage) against a chemical preservative (Allprotect™ Tissue Reagent (Qiagen, Germantown, MD, USA)) and freezing at -20 °C. Bovine muscle tissue, used as a proxy for human tissue, was treated with the four preservation methods and sampled at six different time-points over a 24-month period. All four methods were able to preserve the bovine tissue, generally yielding STR-PCR (Short Tandem Repeat-Polymerase Chain Reaction) amplicons > 200 bp in size even at the end of 24 months. Gel electrophoresis, however, indicated that salt was more effective in preserving DNA integrity with high-molecular-weight DNA clearly visible as compared to the low-molecular-weight DNA smears observed in the other methods. This study also proposes a simple process for the rapid and low-cost preservation of tissue samples for long-term storage at ambient temperatures in support of post-incident victim identification efforts.

Identifying container hotspots for table grape exports from South Africa to the UK: A case study

In view of table grapes being very sensitive to temperature variations, steps must be taken to maintain temperature at protocol levels to avoid deterioration of fruit quality and resultant food losses. This study assesses the implications of hotspots in refrigerated containers during table grape exports from a packhouse in South Africa, through the other stages of the cold chain until a retailer’s distribution centre in the UK. Ambient and pulp temperature data were collected from temperature sensors inserted at locations distributed horizontally and vertically throughout the container.The mixed analyses results showed that the most severe temperature deviations from protocol, in terms of the maximum temperatures recorded, occurred during the period from when the pallets were removed from cold storage to be loaded into the reefer container up to when the container was reconnected to an electricity supply at the port. Sensors located in the middle and top of the pallet were far more likely to record temperature deviations compared to sensors located at the bottom of the pallet, implying that hotspots are more likely to form in the upper-half of the container than near the floor.The study, a first that covered the entire export cold chain of table grapes to the importing country’s distribution centre, identified key areas industry role players can concentrate on to improve the operational proceduresalong the cold chain. This was done to help support the South African table grape industry to remain competitive in the global market.

A comparison of different technologies to improve temperature control in refrigerated containers: A table grape export case

PurposeTable grapes are exported in refrigerated (reefer) containers owing to their temperature sensitivity. Previous studies have found that insufficient airflow around pallets of fruit cause hotspots in reefer containers, which could negatively affect fruit quality. This study compared the efficacy of two technologies fitted inside reefer containers to improve airflow for table grape shipments. MethodAmbient and pulp temperature sensors were inserted in two shipments of three containers each; each shipment had one container fitted with airflow Technology 1, one fitted with airflow Technology 2, and a control container. Sensors were placed in cartons in the top, middle and bottom layers of six pallets per container to obtain the ambient and pulp temperature profiles of table grapes along the export cold chain from the cold store in South Africa until the destination distribution centre in the Netherlands. Descriptive statistics and two-way ANOVA tests were used to analyse the datasets. FindingsThe largest number of temperature breaks and the longest temperature breaks were recorded in the control containers. Overall, the containers fitted with airflow technologies fared better than the control containers. The containers fitted with Technology 2 performed marginally better than those fitted with Technology 1. However, the sample size of this study was too small to draw definitive conclusions. Further research with larger sample sizes is required for more definitive results. OriginalityThis article identifies areas along the table grape export cold chain where temperature deviations occur more frequently and links the temperature deviations to product quality. It also ascertains which airflow technologies can help to limit the deterioration of product quality and cut financial losses.

THE METHOD OF OBTAINING IONIZING RADIATION BASED ON THE EFFECT OF BRAKE RADIATION

The main problem of the decommissioning of nuclear installations (NPPs) is the processing or disposal of radioactive waste. The main method is the burial of radioactive waste (RAW) in special refrigerated containers that require constant supervision and maintenance. As a result, we have a large area with RW that needs to be maintained, protected and serviced. An alternative is to recycle waste to reduce its dimensions and possibly reuse it. Taking advantage of the phenomenon of bremsstrahlung, it is possible to obtain radiation with a defined energy spectrum. It is possible to ionize the atoms of a certain isotope, which in turn will make it possible to use the interaction of ionized particles with a magnetic field. The magnetic field will be able to move ionized particles, thereby separating them from non-ionized ones.

Polycaprolactone sub-micrometric fibers optimization for primary packaging loaded with fatty acids as natural phase change materials

Currently, active food packaging is one of the most important means of preserving food quality and reducing losses. Refrigerated and frozen foods are among the most wasted products. However, efforts aimed at temperature control systems are very sparse and limited to refrigerated containers. Therefore, in this work, polycaprolactone fibers optimization through electrospinning is proposed for the production of innovative materials for primary packaging intended for foods subjected to the cold chain. The novelty lies in the substances loaded into the fibers, linoleic and oleic acid, two natural phase change materials. In fact, no work has ever investigated the direct loading of fatty acids inside polycaprolactone fibers. The best set of parameters to obtain sub-micrometric fibers was identified in polycaprolactone at 20% respect to the volume of the solvent composed by acetone and acetic acid 3:7 v/v, processed at 19 kV and 1.7 mL/h. The influence of fatty acids, loaded from 10 to 30% w/w, was evaluated by mechanical tests that highlighted a reduction in polycaprolactone fibers stiffness with tensile strength in accordance with conventional standards. The thermal properties analysis revealed the establishment of chemical interactions between the polyester and the fatty acids with consequent loss of thermoregulation properties. Finally, the migration test conducted in food simulant confirmed the obtainment of non-migratory materials, with release of less than 2% after 14 days. These results, although preliminary, help fill the gap in the architectures of these interesting materials which showed to have the potential to be applied as thermal insulating packaging layer.

Conversion of a military vessel into a civilian refrigerated vessel

River transport is one of the oldest in the Russian Federation. It is of particular importance for the northern and eastern regions, where the density of railways and highways is not high enough, or they do not exist at all. In these regions, the share of river transport in the total cargo turnover is about four percent. The use of river water transport for military purposes will never be stopped. Since requirements that are more stringent are imposed on military transport, the decommissioning of these vessels is faster than in commercial use. In most cases, the technical condition of the vessel is not critical, and it can be further operated. In view of the fact that recycling is a rather expensive process, ships are idle and are not used for their intended purpose. The way out of this situation can be the use of decommissioned military vessels for commercial purposes by converting them into a refrigerator in order to extend the operational life of the vessel, improve the technical and economic indicators of the vessel and make a profit. From the point of view of the methodological approach, the analysis of existing refrigerated containers was carried out, additional devices for converting electricity were given, the technological process of manufacturing the frame of the refrigerator installation was developed, and its strength calculation was carried out. The economic feasibility of converting the vessel into a refrigerator is shown.

Thermal performance and sustainability assessment of refrigerated container with vacuum insulation panel envelope layer at different design forms

The thermal performance of vacuum insulation panel envelope layers at four design forms are explored by computational fluid dynamic. The design arrangement form 1, design arrangement form 2, design arrangement form 3 and design arrangement form 4 have the same coverage percentage of vacuum insulation panels. The insulated performance of the VIP envelope layer is impacted by the thermal bridge effect and the polyurethane distribution. The key parameter W, which affects the thermal bridge effect, is found. As the W value decreases, the thermal bridge effect also decreases. For the operation time of 3600 s, the carbon emission of the envelope layer at the four design arrangement forms are 819.9, 426.8, 407.1 and 340.3 g CO2, respectively. And the average heat flux of the four design arrangement forms are 0.995, 0.518, 0.494 and 0.413 W/m2, respectively. Based on the sustainability assessment, the design arrangement form 4 is the best design form for small and medium-sized refrigerated containers. If the size of the VIPs could be customized, the W value will be equal to 0 and the heat leakage caused by PU gaps can be avoided which can enhance the insulated performance of small and medium-sized refrigerated containers.

An efficient entropy-based stopping rule for mitigating risk factors in supply nets

Potential supply-net risk factors include capacity issues, currency volatility, design changes, frequent changes in tax regulations, unsafe information systems, and port shutdowns. Such risk factors make it challenging for decision makers to design efficient risk-management procedures and minimize the operational costs associated with mitigating these risks. Since complete information about all risks is generally not available, we utilize an axiomatic approach, based on the notion of entropy, to develop an efficient solution procedure. The strategy involves developing a stopping rule that enables the decision maker to decide online whether or not to continue investing in the acquisition of information about risk factors. The problem is formulated as a non-linear integer optimization model. We develop sufficient conditions for the entropy function such that a unique global solution is obtained.A case study that addresses risks associated with the transportation of aquatic products in refrigerated containers demonstrates the superior performance of the stopping rule relative to a standard risk-assessment procedure. In addition, numerous computerized experiments are carried out, under different problem settings, to compare the stopping rule with an anticipative optimum. The cost incurred when using the stopping rule is found to be no more than 0.4% higher than the cost of the anticipative optimum (the lower bound for the objective). These findings clearly demonstrate the efficiency of the proposed stopping rule for a wide range of problem sizes.

System design and analysis of refrigerated containers utilizing LNG cold energy

In order to solve the problems of excess cold energy of the fuel and large power load required for refrigeration of refrigerated containers on LNG powered container ships, this study proposes a scheme to use the fuel cold energy of LNG powered container ships for refrigerated containers, the process simulation software Aspen HYSYS is used to simulate the cold energy utilization scheme, with the help of MATLAB, the multivariable optimization research on the cold energy utilization scheme of LNG powered container ship is carried out, taking the cold energy utilization rate of LNG cold energy scheme as the objective function, the LNG cold energy utilization scheme is optimized.

Multiobjective optimization of railway cold-chain transportation route based on dynamic train information

Freight train is selected to pick up and hang refrigerated containers according to railway freight train diagram in China. A multiobjective optimization model of railway cold-chain transportation route is established with total, time, and reliability costs as objective functions on the basis of dynamic train information. Different weights of three objective functions are obtained and weighted sum method is used to transform the multiobjective problem into a single-objective problem according to different transport demands of railway cold-chain transportation participants. An example of k short-circuit optimization algorithm based on genetic algorithm (GA) is designed to prove the feasibility and effectiveness of the proposed model. The empirical analysis showed that different transport times can be obtained by adjusting weights of various optimization objectives in the model to meet diverse needs of railway cold-chain transport participants and selecting differentiated shifts and transfer stations on the same route to provide a variety of transportation time limit options. Results of this study can provide guidance to decision makers in choosing railway transportation schemes.

Creation of supply chains for the delivery of agricultural products and food along the Eurasian transport corridors

To assess the advantages of the supply of agricultural products and food in specialized refrigerated containers, to show the main channels for the supply of food cargo by container trains on Eurasian transport routes. Research methods: when preparing a scientific article, methods of scientific research in logistics were used: structural analysis, technical parameterization, process analysis of supply chains. Results: the advantages for cargo owners of the service of food shipments by specialized refrigerated container trains are substantiated, visual diagrams of geographical routes of food shipments in the direction of Russia - China are presented, descriptions of survey logistics services, Glonass navigation services and tracking of the location and temperature regime of the transported container are given. Recommendations: the results of the published study are recommended to be used by specialists of logistics services of cargo owners in the process of designing the delivery and shipment of food cargo according to seamless multimodal delivery schemes.

Analysis of the use of aerogel as a thermal insulator in refrigerated containers for storing blood using a photovoltaic system

At the beginning of the present, a comparative analysis was carried out between polyurethane as a traditional thermal insulator and aerogel as an insulating material that has excellent thermal properties; the analysis is carried out through a container for storing blood, in which calculations of thermal loads were performed. In addition, a photovoltaic system is proposed to supply energy to the container. As a result, the energy consumption of the system is obtained, using the proposed insulators, resulting in lower consumption when aerogel is used.

Is there a systematic hidden 'hot spot' in refrigerated containers filled with fresh food in ventilated packaging?

BackgroundThousands of refrigerated containers transport fresh fruit and vegetables to feed the world yearly. These containers should preserve fresh-food quality as uniformly as possible throughout the cargo. Scope and approachSeveral simulation studies have suggested the presence of a systematic hot spot in these containers near the supply-air inlet when warm cargo is cooled down in the container. Induced by airflow recirculation inside the ventilated packaging, the hot spot is located at the bottom of the pallets near the refrigeration unit. The fruit at the bottom of these pallets is well known to be exposed to cold air. However, the existence and impact of this apparent hot spot were not acknowledged explicitly. Interestingly, full-scale experiments and computational fluid dynamics (CFD) simulations contradict the existence of this recirculation-zone-induced hot spot. Key findings and conclusionsWe analyzed the literature and the physical phenomena at play to identify if and why this recirculation-driven hot spot occurs. We found that the airflow recirculation can be partially hidden in full-scale experiments and that we are often not looking for it at that location. Physically, the presence of the recirculation zone is plausible. The CFD simulations that predict this zone include all relevant physical processes. However, we still need proof by detailed full-scale experiments to confirm its existence. It is likely that the recirculation only occurs in some ventilated shipments, but then we need to identify for which shipments this happens. If this recirculation zone is present in a ventilated cargo of perishables, we need to solve this problem urgently. We suggest a roadmap with steps to do so. Otherwise, we would be systematically losing food quality in many shipped containers. Besides slowing down fruit cooling, such a recirculation vortex can trap respiration heat, moisture, and metabolic gases. Mitigating this hot spot thus can considerably impact the quality of the fruit and vegetables shipped worldwide.

Research on the utilization of fuel cold energy for LNG powered container ships

Aiming at the problems that the fuel releases a lot of cold energy and the refrigerated containers consume a lot of electricity on large LNG powered container ships, a set of cold energy cascade utilization scheme that mainly uses LNG cold energy for refrigerated containers is designed. The simulation software Aspen HYSYS is used to establish and simulate the process of the ship’s cold energy cascade utilization system under five different working conditions, and the main parameters of the key nodes are obtained, according to the established exergy efficiency model, the exergy efficiency of the main equipment and the whole system is solved. Under the five working conditions, the maximum exergy efficiency of the refrigerated container system before optimization is 24.54%, at this time, the exergy efficiency of the entire cold energy utilization system is 24.86%. With the goal of improving the exergy efficiency of the entire system, using a hierarchical optimization method, the key parameters affecting the exergy efficiency of each cold energy utilization module are analyzed and optimized respectively, and the optimal operating parameters of different cold energy utilization module were determined. So as to realize the optimization of the whole cold energy cascade utilization system. The results show that the exergy efficiency of the optimized LNG cold energy cascade utilization system for ships under five working conditions is improved, under the 65% working condition, the exergy efficiency of the optimized refrigerated container system is 27.69%, and the exergy efficiency of the whole cold energy utilization system is 28.04%, which are increased by 3.15% and 3.18% respectively. Which proves that the LNG cold energy cascade utilization system can realize the effective utilization of LNG cold energy.

Exploring novel carton footprints for improved refrigerated containers usage and a more efficient supply chain

Large quantities of fresh produce are exported every year to international markets across the world using refrigerated freight containers (RFCs). However, many packaging systems are legacy designs for older shipping technologies. For fruit, more than 10% of the RFC floor area is unused by current packaging systems, and designs often do not facilitate adequate cooling conditions. This study showed that novel packaging designs could improve packing density by up to 19%. Two new packaging systems were investigated using CFD to emulate conditions similar to forced-air cooling (FAC) and a RFC, respectively. The proposed packaging increased floor area utilisation to about 98%. The FAC energy efficiency was improved by 29%. An analysis of the results indicates considerable cooling improvements are possible by modifying vent hole designs and using taller cartons. The study thus demonstrated substantial merits to implementing new fruit packaging systems.